Dining / Cooking

Preserve the bounty of tomatoes through canning, dehydration or freezing

By Gwen Schoen | Wednesday, August 20, 2008 | () comments

Just a couple of months ago, the great tomato scare began to single out some versions of our summer icon as suspects in a salmonella outbreak that has sickened hundreds. But tomatoes of all types from all sources eventually were found not guilty in the U.S. Food and Drug Administration’s probe.

By all accounts, only one delicious problem remains: using up those red baubles about to begin piling up like bocce balls in offices, on doorsteps and in markets. Not to worry: We’re about to share some ideas on how to devour and preserve them.

Once you get them home or out of the garden, store them at room temperature, never in the refrigerator. The refrigerator causes the juice to separate from the pulp. Also, chilling causes tomatoes to stop ripening. You can speed up the ripening by storing them in a brown paper bag.

If you are lucky enough to have an abundance of tomatoes, there are several ways to preserve the bounty. Depending on how you want to use them, they can be canned, dehydrated or frozen.

Canning

There are two basic canning methods: water-bath canning, used for high-sugar or high-acid foods such as fruit, pickles, tomatoes and jams; and pressure canning, for low-acid items such as beans or meat.

Tomatoes, because they are considered high-acid, can be water-bath canned. The food is packed into sterilized Mason-type jars, liquid is added and a sterilized lid is placed on top of the jar. The filled jar is submerged in a pan of simmering water for a specified processing time.

Because many food-safety factors are involved, it is important to follow instructions and use recipes from a reliable source. Recipes from the Kerr and Ball companies (the companies that make canning jars and tools) are among the best.

It’s also important not to use old family recipes. Tomatoes grown today, for example, are not as acidic as those grown years ago, so it’s necessary to add lemon juice or vinegar to them before water-bath canning.

Dehydrating

Drying is one of the oldest methods of preserving foods, said Judy Mansfield, a master food preserver. She and her husband, Darryl, often demonstrate dehydration techniques at a University of California Cooperative Extension office in Sacramento.

“Dehydrating is very simple, and you don’t have to have a dehydrator to do it,” she said. “Having a good dehydrator is helpful but not necessary.”

“The problem with dehydrating is that the food tastes so good and it has been reduced in size so much that it’s easy to eat too much,” Mansfield said. “The calories are still there — just the water has been taken out.”

Preparing tomatoes for dehydrating is easy. Just wash and dry them, then cut the tomatoes into small pieces. The Mansfields often cut them into quarters or small julienne slices.

If you are using a dehydrator, place the pieces on drying trays, then put those in the machine and follow the instructions that came with it. Drying takes six to eight hours, depending on the size of the pieces and the moisture content.

To dry tomatoes in the oven, wash and slice them, and place them on clean screens or racks. Set the oven to the lowest setting, 150 degrees or lower. Place the racks inside and leave the door ajar while the tomatoes dry. Drying will take about six hours, and you will probably need to rotate the racks halfway through the drying time.

For sun-drying, the weather needs to be about 85 degrees. Place the sliced tomatoes on clean screens and cover them with cheesecloth. Prop the cloth up so it does not rest directly on the tomatoes. The cheesecloth is simply to protect the tomatoes from bugs. Drying will take two to three days, and you will need to bring the screens in at night to prevent moisture buildup.

No matter which method you use, when properly dried, the tomatoes will be pliable but not sticky or hard. After drying, place the tomatoes in a tightly sealed plastic bag. If they develop condensation, they are not dry enough. Then freeze the tomatoes for 24 hours to kill any bugs. Finally, pack the dried tomatoes in jars.

Two weeks before you want to use dehydrated tomatoes, place them in a small amount of vinegar or lemon juice and toss to cover. Then drain them on paper towels. Add seasonings to a clean jar, then add the tomatoes and fill the jar with oil. Store them in the refrigerator, and in two weeks they will be ready to eat.

Calories and fiber amounts do not change during dehydration, but dried tomatoes will lose a small amount of vitamin A and some other vitamins and minerals. Dehydration destroys nearly all of the vitamin C.

Freezing

Tomatoes are not great when frozen, said Dennis Prendergast, a master food preserver who lives in Orangevale, Calif.

“They tend to get mushy, but you can make sauce to freeze, and that works just great,” he said.

For freezing, start with firm, ripe tomatoes. For best results, remove the peels.

To remove the peels, bring a pot of water to a boil, dip the washed tomatoes in it for 30 seconds and then drain them. The skins will slip off easily.

Pack whole or cut tomatoes in freezer containers, leaving 1 inch of head space to allow for expansion. Seal and freeze them. They will keep in good quality for about a year.

You also can make sauce using your favorite recipe, then freeze it in freezer containers leaving an inch of head space.

PASTA WITH MUSHROOMS, SUN-DRIED TOMATOES AND PINE NUTS

Serves 4

12 sun-dried tomatoes (not oil-packed)

2 cups boiling water

Nonstick vegetable oil spray

1 pound mushrooms, thickly sliced

1 large onion, chopped

1 cup dry white wine

2 large garlic cloves, chopped

12 ounces penne pasta, uncooked

1/2 cup grated Parmesan cheese

1/4 cup pine nuts, toasted

1/4 cup sliced fresh basil or 2 teaspoons dried

Salt and pepper to taste

Place sun-dried tomatoes in a small bowl. Pour 2 cups boiling water over them. Let stand until tomatoes soften, about 15 minutes. Drain tomatoes, reserving the soaking liquid. Thinly slice the tomatoes.

Spray a large, nonstick skillet generously with vegetable oil spray. Add mushrooms, onion, wine, garlic, reserved tomato soaking liquid and sliced tomatoes. Bring to a boil over high heat. Reduce heat to medium and simmer until liquids are reduced by half and vegetables are tender, about 25 minutes.

Meanwhile, cook the pasta in a large pot of boiling, salted water until just tender but still firm to the bite. Drain the pasta, reserving 1 cup of the cooking liquid. Return the pasta to the same large pot.

Pour sauce from the skillet over the pasta. Add the Parmesan cheese and pine nuts. Toss, adding reserved cooking liquid by quarter-cupfuls if the mixture is dry. Mix in basil. Season to taste with salt and pepper.

— Source: Bon Appetit magazine

MUSHROOMS STUFFED WITH SUN-DRIED TOMATOES

Makes 18

This is a tasty way to use sun-dried tomatoes for appetizers.

1/2 ounce dried tomatoes (about five large pieces) not packed in oil

2 tablespoons olive oil

18 white mushrooms

1/4 cup finely chopped shallots

1/3 cup finely ground dry breadcrumbs

1 large egg yolk, lightly beaten

1/4 cup fresh parsley leaves, minced

1/2 teaspoon dried basil, crumbled

2 tablespoons freshly grated Parmesan

Preheat the oven to 350 degrees.

In a small bowl, soak tomatoes in hot water to cover, 5 minutes. Reserving 1 tablespoon soaking liquid, drain the tomatoes well and chop fine. Remove stems from mushroom caps and chop the stems finely, reserving the caps.

In a small skillet, heat oil over moderate heat until hot, but not smoking, and cook the chopped mushroom stems and shallots, stirring until shallots are softened.

In a bowl, stir together the mushroom mixture, breadcrumbs, tomatoes, reserved soaking liquid, yolk, parsley, basil and salt to taste. Mound stuffing in reserved mushroom caps and arrange caps in a lightly greased shallow baking dish. Sprinkle mushrooms with Parmesan and bake in middle of the oven for 15 minutes.

— Source: Gourmet magazine

Gwen Schoen can be contacted at gschoen@sacbee.com.

FOR MORE INFORMATION

You will find more information and recipes for preserving tomatoes and other vegetables on the Web site for the National Center for Home Food Preservation, www.uga.edu/nchfp.